The present invention relates to an orthodontic bracket. More particularly, the orthodontic bracket of this invention comprises a bracket body with a mesial-distal slot for the reception of an archwire, and a resilient locking loop member which has a closed position for retaining the archwire in the bracket slot and an open position to allow the archwire to be removed from the bracket slot or inserted into the bracket slot.
Orthodontic archwires are generally made of resilient wire and have a shape and form of a smooth flowing arch which approximates the arch form of the labial surfaces of normal teeth in a normal dental arch.
The archwire is inserted into brackets, which are fixed to the teeth, and then locked into the brackets by various means. The most widely used means of locking the archwire into brackets is to use elastomer "O" rings and/or soft temper stainless steel ligature tie wires. Placing and removing the "O" rings and ligature wires is a time-consuming and tedious task. Elastomer "O" rings loose their elasticity in a very short period of time in the mouth. When this happens, the forces they originally produced to help the archwire straighten the teeth are no longer present.
The new bracket described herein will save valuable time. To tie an archwire into a slot with stainless steel ligature wire, and later remove the ties, takes approximately 30 seconds per tooth. "O" rings require approximately 15 seconds per tooth. To lock and unlock the bracket of the invention will take approximately 5 seconds per tooth. The average orthodontic case will use these brackets on 18 teeth. Therefore each routine of insertion and removal, by the respective methods, requires the following comparative times:
______________________________________ Ligature Time to Place and Remove Archwire 9 Minutes Wire 18 .times. 30 Seconds = "O" Ring Time to Place and Remove Archwire 4.5 Minutes 18 .times. 15 Seconds = This Time to Place and Remove Archwire 1.5 Minutes Invention 18 .times. 5 Seconds = ______________________________________
The average orthodontic case requires 10 archwire changes or adjustments for each arch (upper and lower), or 20 in-and-out routines. Therefore:
______________________________________ Ligature Wire Time 180 Minutes "O" Ring Time 90 Minutes This Invention Time 30 Minutes ______________________________________
These routines typically take place over a two year period.
A typical orthodontic treatment requires a series of archwire changes during the course of treatment. At the beginning of treatment the teeth are in their most extreme malpositions. This requires the maximum distortion of the archwire to get working engagement in the bracket slot; therefore, cases are typically started with small diameter, very resilient archwires. As the teeth slowly move, larger and larger diameter archwires replace the smaller archwires. As the case progresses further, round wires are replaced with square or rectangular archwires. The final finishing archwire is usually rectangular in cross section and of a size that fills up the bracket slot with only about 0.002" freedom of movement in the bracket slot. This large finishing archwire is extremely stiff compared to the archwires used earlier in the treatment and is used chiefly to hold the teeth in a solid passive position until the roots of the teeth become stable with the supporting skeletal structure.